Tracing environmental change in southern Patagonia using beryllium isotopes, Laguna Potrok Aike, Argentina

Abstract

We have examined the relationship between beryllium isotopes and the hydrological record of Laguna Potrok Aike, a maar lake in southern Argentina for the past 16,000 cal BP. Our study shows that sedimentary 10Be and 9Be records of Laguna Potrok Aike are associated with the hydrological balance, when compared to other proxies such as Ca, Ti and total inorganic carbon (TIC). During drier periods, the level of 9Be is decreased. 10Be follows this trend from 16,000 to 8000 cal BP, for younger samples, the concentration of 10Be increases at about 5000 cal BP and in recent times, but is otherwise relatively constant. At 13,000 cal BP total beryllium (9Be) was relatively low, but the 10Be/9Be ratio was the highest for the entire record studied. Our study shows that beryllium isotopes can be used for tracing climatic signals associated with lake level changes, i.e., dry or wet conditions at Laguna Potrok Aike.